Farage has said his party will not accept any more defectors after local elections are held on 7 May.
"Any Conservative MP who still clings to the hope that their party can recover and waits until May 8 to try to leave the sinking ship does not understand how rapidly things are changing out in the country," he wrote in the Telegraph.
"Trying to use Reform as a lifeboat to save their own political skins will not wash. We have no interest in rescuing political failures."
He said any defectors would have to bring some benefits to the party and "truly believe in Reform's fundamental values of family, community and country".
Senior Conservatives believe some other MPs could also defect, though they are not expecting a big wave of departures imminently.
